The core activity of APJ Sàrl is the execution of high-end services in the field of watchmaking, particularly in the following three domains: 1. **High-End Polishing**: The company polishes high-quality materials such as gold, platinum, steel, stainless steel, titanium, and ceramic for watch components like cases, backs, bezels, pushers, crowns, and balance wheels. 2. **Movement Decoration**: APJ Sàrl offers various decoration techniques for watch movements, including sunburst, circular graining, Geneva stripes, pearling, circular brushing, satin finishing, and hand anglage. 3. **Finishing and Treatment**: The company specializes in various polishing and treatment techniques, including mirror polishing, black polishing, random polishing, and chemical polishing.